Device for removing a gas from a liquid



July 13, 1965 w..1. KUDLATY DEVICE FOR REMOVING A GAS FROM A LIQUID Filed Jan. 8, 1962 Mr/Veys United States Patent O 3,193,933 DEVICE FOR REMOVING A GAS FRM A LIQ Walter J. Kudlaty, Elmhurst, Ill., assigner to Flick- Reedy Corporation, a corporation of illinois Filed Ilan. 3, 1962, Ser. No. 164,793 Claims. (Cl. 55-10) This invention relates to a liuid deaerator. Generally the invention is concerned with a unit which can purge or remove air from a hydraulic liquid, particularly the petroleum oils. The unit may also be useful in separating a mixture of gas and liquid.

In hydraulic systems various liquids may be used and in general various petroleum oils are employed. Air can be dissolved in hydraulic liquids with very little effect upon the operation of the hydraulic components so long as the air remains in solution. Air may enter hydraulic systems at various locations, through pump suction lines, around faulty packings or through other mechanical defects. It has been authoritatively specified that most commercial oils contain about ten percent of air by volume in solution. When oils are subjected to higher pressures, the amount of air by volume whichV can be dissolved in the oil increases tremendously.

Air'dissolved in a hydraulic liquid comes out of solution under various conditions which are generally present in a hydraulic system. Any cavitation which occurs in the system will have the tendency to cause the air in solution to come out and form a bubble within the hydraulic liquid. These undissolved amounts of air in aV hydraulic system cause erratic, unpredictable, and otherwise unwanted failures of correct operation by hydraulic components.

It is therefore the principal object of this invention to provide a device which will when incorporated in a hydraulic system automatically operate to remove and purge gaseous medium from the hydraulic fluid employed.

Another object is to improve the ability to precisely meter and position hydraulic components by the elimination of air from hydraulic fluid, and particularly, from petroleum oils.

Another object is to remove entrained air from hydraulic fluid in order to minimize oxidation thereof.

Another object is to provide a unit which will automatically add hydraulic fluid to a system when conditions in the system provide for cavitation.

Another object is to provide a unit automatically operable to relieve excessive hydraulic pressure which may exist in a hydraulic system due to restriction or to ternperature rise therein.

A further object is to provide a unit capable of preparing a hydraulic liquid for use in a system by the removal of gas from the liquid.

Other objects, features and advantages of the present invention will be apparent from the following description of embodiments of the invention illustrated in the accompanying drawings, in which:

FIGURE 1 is a diagrammatic flow diagram of a positioning control unit embodying the present invention;

FIGURE 2 is a vertical sectional view through the center of the tank unit shown uppermost in FIGURE l;

FIGURE 3 is a horizontal sectional View through the tank unit taken substantially along line 3 3 in FIG- URE 2;

FIGURE 4 is a fragmentary sectional view through the valve' structure in the tank unit taken substantially along the line 4 4 in FIGURE 2; and

FIGURE 5 is a diagrammatic llow diagram showing a unit capable of preparing a hydraulic liquid for use in a hydraulic system.

Y Referring to FIGURE 1, there is shown an air cylinder having air line connections 11 and 12 for driving a 3,l93,988 Patented July 13, 1965 ICC piston rod 13 visible on the left hand end of the ligure. The air cylinder 10 provides the motive force for the movement of the piston rod to the left and right as shown in the ligure. In tandem with the air cylinder is a hydraulic cylinder 14 used for accurately positioning the piston rod 13 through metering a definite volume of oil into one end or the other of the cylinder. For this purpose the piston rod 13 has a piston 15 thereon within the hydraulic cylinder 14. The piston 16 in the air cylinder is also connected to the same rod to provide the motive force specified. Hydraulic lines 17 and 18 are connected to opposite ends of the hydraulic cylinder with a metering valve 19 and a needle valve 20 in one of the lines for controlling the flow therethrough. A tank unit 21 is also connected in the lines 17 and 18 for the purpose of purging air from the hydraulic fluid used. The lines 17 and 1S may be connected respectively to either end of the hydraulic cylinder 14 to effect positioning and control of the piston rod 13 as desired. The air-oil tank unit 21 has port means 22 and 23 open to atmosphere.

Air in the hydraulic liquid used in the system shown in FIGURE l can result in inaccurate placement of the piston rod 13. Desirable operation requires that the metering of the hydraulic liquid be quite accurate and unaffected by any air which comes out of solution in the liquid. It is known that the provision of a suddenly enlarged area in the flow path can cause cavitation in a hydraulic system. Air previously in solution has a tendency to come out of solution in areas where cavitation occurs. The presence of an air bubble in the liquid can cause erratic metering and Vresultant inaccurate positioning of the piston rod 13. It has also been found that metering devices generally pass fluid in accordance with the input pressure. With the presence of air in hydraulic fluid, pressure may rise with the temperature very rapidly. The presence of the air also under such ternperature rise conditions may have the affect of causing local oxidation developing sludge in the oil affecting the operation ofthe hydraulic components adversely.

In the present vsystem a unit is provided for removing from the hydraulic liquid any air Which may become separated or come out of solution in the liquid. To insure that conditions in the system are such that cavitation can occur for the purpose of releasing air from the hydraulic oil, the needle valve 20 may be placed in the piping 18 leading to the air-oil tank 21. The needle valve insures the presence of a zone in which a pressure drop will occur which in turn allows dissolved air to come out of solution in the form of bubbles. The operation of the tank is such that its structure will remove these bubbles of air from the liquid.

Referring particularly to FIGURES 2 to 4, inclusive, it will be observed that the tank has a lower chamber 25 surmounted by an upper chamber 26 formed by three heads and intervening cylindrical sections. The lower head 27 is square in configuration and is provided with a cross bore 28 to which piping 17 and 18 may be connected. A central longitudinal passage 29 provides access for 4a hydraulic fluid to enter the chamber 25 below a baille 30. Preferably the baille which is for the purpose of preventing aeration of the incoming liquid, may be constructed in accordance with Patent No. 2,683,463. The lower chamber side walls are formed by a cylindrical section 31 joined with the lower head 27 and intermediate head 32. Suitable sealing rings 33 and 34 are provided at each end of the cylindrical walls and the walls pilot on the outer portion of the groove in each of the heads. The central head 32 is also square and its under/surface 35 is conical in shape and sloped up to the central area so as to guide any air bubbles in the liquid to the high point in the lower chamber 25.

The upper chamber 26 is formed by the central head 32, a cylindrical yside wall 36, and an upper head 3'7. vSuit- Y able packing rings 38 and 39 Yat each end-of the cylm-v drical wall join the heads and wall together.; .Tie rodsV 40 in the corners of the square heads jointhe three rheads and two `cylindrical sections togetherinto a single unit.

Any air in the-system which comes out of solution because of the'cavitatio'n'at therneedle valve 20 will find itsY wayinto the air-oil tank 21' and automatically be ree moved from the liquid; As the oil renters the lower chamber 25, it passes between Vthe baffle 30 and its supporting legs 39a into the lower chamber. Here the airjbubble rises to the top of the chamber through the liquid. Ther liquid is, ofcourse, at whateverpressure exists in the 'hy-V draulic system 4sine-e it is connected directly with that sys-V tem. The air bubble will'rise Ytothe central area of the Y intermediate headby its ownl buoyancy. At this pointV valve means prevent the movement of thel airV bubble into the upper chamber until there is a` pressure rise in the tion is prevented.

mediately add liquid to that chamber from the upper chamber. No cavitation because of suction conditions is thus allowed to occur and aeration because of such cavital The present deaerating unit maybe used in a hydraulic system by the placement of thejunitr'at various, high points :in Yasystem. The springsv 5t) andrrSl may be chosen in vstrengthl to ,provideA a resilient VVurging of the valve to lower chamber to unseat the blockingvalve. YIn' the present invention theY valve which can allow the air `and liquid both ton rise intoYV the upper chamber is completely submerged. VIn theY upper chamberthe oil levels-1 is above the valve structure'` t The'valve itself comprises an outer spool 45 generally circular in form with a pair of flats v46 on Opposite sides.

The opening 47 through the intermediate head 32 is .cir-Y cular cylindrical and provides the only'passagelfrom the Y lower to the upper chambers; The spoolY 45 fis Yguided in the passage '47 and closes Vthe passage'rby engagement. of

an outwardly'extending circular flange 4S engaging the flat bottom surface 49 of the intermediate head 32. The spool is Yurged Vinto contact with the head and thus'into closed position by' two coil springs. 1 One spring 50 is Yof predetermined strength and engages bothv theange 48 on the spool and the upper head 37. :The second'sprng 51 is of adjustablevcompression in that its upper end restsV upon a supporting base 52 adjustable vertically by means!V Y' of an adjusting screw 53 whichV supports and carri'esit. A

sealing nut 54 about the screw on'the exterior of thefphead 37 preventsany leakage Vout of the upper chamber Vshould Y conditions provide that the upper chamber belunder a pressure, above atmospheric butY lower than thatinthe lower chamber.

By the structure just described a bubble ofair'in 'theV lower chamber may nd its w-ay upthrough the passage l 47 to a position just below the flange 48 on the outer spool` of the valve. A slight Vpressure rise in theY system will momentarily lift the spool allowing the air bubble to escape into the upper chamber.Y Once'the air is above and past thevalve ange 48, it may rise into'thel air space above ythe liquid level 41 in the upperchamber.4 A pas--4 sage 55 is provided'to atmosphere so that theair may be'V vented. YIn some instances pipingv may beconnected with this passage leading to a sump or to'V another vessel.'

The present deaerating unit also provides fort-he auto-V matic addition of'oil to a system whenever suction'con-VV` ditions exist inthe system. To elect the addition'of oil Y to the system a port 56 maybe provided in thefupPBr head for the addition of Oilfinto theA upper 'chamber 26. Y` A light Weight valve is incorporated in the spoolAS soV as to be sensitive and responsive to a suction condition in Y the lower'chamber 25 tov admit oil into the lower cham'- ber. Thespe'cic valve is ank'elongated spool 57 witlra closed position yagainst whatever pressure is being used in Yl0 a particular system. The solidil'ication A0f the hydraulic Viiuidl results'from the eliminationfof the air and once the an orifice or other restriction `63 provided to insure that cavitation occurs.Y The air-oil tank unit 21 is similar to that described, however, ,theV hydraulic oil supply line 23 may be'connected to a source of oil to vbe treated and a line fromfthe-,lowerv chamber forrat alow-point in the lsystem may be led to areservoir forwtreated oil. It has 'Y been: found that a s hort periodV of use 0f theV deaerating Vunit may *resultY in oil inY which any air remaining will remain inra dissolved state and thus not adversely aect either meteringV or proper operation of hydraulic components. i

The foregoing detailed description has been given for clearness of understanding'ionly, and no unnecessary limi- Y.tations should be understood therefroml for some modi'- fications will be obvious to those skilled in the art.

Igcl'a'im: Y l l. Aydevicerfor purging air from hydraulic liquid in a system having means causingV air to come outof solu- Vtion in the'hydraulic liquid, comprising: an air-oil tank unit having a lower chamber for connection with the system to receive hydraulic liquid therein, said tank unit having an upper chamberabove the lower chamber with means providing a single passage for communication between thejchambers and valvermeans -in such passage Y connecting Vthe chambers, said valve means being mounted respectively at 4a high area in the lower chamber and a low area` in the upper chambensaid valve means vhaving Y a valve closure resiliently urged closed against pressureV il in the Ylower chamber, said valve closure kforming the solef gas outlet :and being responsive vto pressure in the lower'chamber in excess of said resilient urge to pass air f and liquid from the lower chamber into the upper chamber, said upper chamber having means vfor passage of theair therefrom, said Yvalve'means carrying a member Y responsive to suction in the lower chamber for passing ange V58 at itslower end engaging the lower end ofthe A outer valve spool 45. VAs seen V,best in FGURE 4,r thel spool 4S andspool 57.

This valve ismaintained closed by a small Vcoil spring 'L' 59 which holds the spoo157 Vin'its upperposition. This springl 59 is sufficiently strongto support Y'the Vweight ofV i' ture with a liquid, comprising: a liquid land gas. tank unit the spool 57 but allow the spool tobe moved downwardly 'Y quickly'V under inuence of lany suction in the lower cham-V =ber 25.' Any surge in the hydraulic system which causes the withdrawing of liquidlfrorn therlchamber V25 will iminner spooly 57 also is provided with Yflat-sides 58 form: 65j

l Ving a'spacethrogh which the oil mayjr'pass between rthe Y only liquid into the lower chamber from the upper cham'V ber. Y Y l Y l,

Y2. A r device vfor removal of air from hydraulic liquid, ,comprislng anair-'oil tank unit 'having a lower and upper chamber, the lower chamber having a connecting port for passage of hydraulic liquid into 'fand outrof the lower Ychamber of the tank'unit, and valvemeans Vcomprising the sole connection Ybetween said chamberspsaid v valve Y means havinga first part responsive topressure inthe lower chamber to open for passage rst of separated air followed by liquid from the lower to the upper chamber,

and .a second part'responsivertosuction in the lowerV chamber Ytoipass onlylliquidrom the upper chamberv into thelower chambenlzand means for removing the separatedl air from the upper chamber.A 'A .y Y Y' 3, A device for removal of gas fromlsolutionY and mixhaving ports for connection rwith `a system containing the 'liquid' from which the gas is to be removed, said tank unit `having a pair of Vchambers one above the Vother kand l' automaticallyr opening,- biasedV closedv valve means connecting the chambers, said valve means being located at a high point in the lower chamber and having separately acting parts, one part being responsive to superatmospheric pressure in the lower chamber to pass gas and liquid upwardly only from the lower chamber to the upper chamber and another part responsive to suction pressure in the lower chamber to pass liquid from the upper chamber into the lower chamber whereby bubbles of gas in the liquid may be discharged into the upper chamber, said upper chamber having means for discharge of said separated gas.

4. A purging unit for separation of gaseous medium mixed, entrained or absorbed in a liquid medium, comprising: a tank unit having a pair of chambers one above the other, port means solely in the lower chamber for connecting the lower chamber to a source of said liquid medium, first biased closed valve means between the chambers responsive to pressure in the lower chamber for opening to pass gaseous and liquid medium upwardly into the upper chamber, and second biased closed valve means responsive to suction in the lower chamber for opening only to pass liquid medium from the upper chamber into the lower chamber, said Valve means and port means comprising the only outlets from said lower chamber, and means communicating with the upper chamber for conducting the gaseous medium out of the upper chamber.

5. Apparatus for removing air from a hydraulic system and replenishing the system with hydraulic liquid as the system requires it, comprising: a hydraulic system; a tank unit connected at its lower end to ahigh point in the system and having a first lower and second upper chamber, the first chamber having a lower passage in its lower portion connecting the chamber with the hydraulic system, said first and second chambers being connected by a valve spaced above said lower passage and biased closed against the pressure in said first chamber, the upper surface of the lirst chamber sloping upwardly to the valve to facilitate an accumulation of air bubbles below the valve when the iirst chamber is filled with fluid, said valve being responsive to fluctuation of system pressure to allow air first and liquid thereafter to pass from the first chamber to the second chamber; and a quantity of hydraulic liquid in the upper chamber submerging the valve, said valve including a portion biased closed against flow of such quantity of liquid into the lower chamber and being responsive to suction in the lower chamber permitting such flow to replenish liquid to the system.

References Cited bythe Examiner UN TED STATES PATENTS 2,413,102 12/46 Ebert et al. 55-55 X 2,660,259 11/53 Morehouse 55189 2,768,704 10/56 Cronkhite 55-168 X 2,995,147 S/61 Bergquist 251-118 X FOREIGN PATENTS 681,089 9/ 39 Germany. 151,136 9/20 Great Britain.

REUBEN FRIEDMAN, Primary Examiner.

MARTN SCHWADRON, Examiner. 

1. A DEVICE FOR PURGING AIR FROM HYDRAULIC LIQUID IN A SYSTEM HAVING MEANS CAUSING AIR TO COME OUT OF SOLUTION IN THE HYDRAULIC LIQUID, COMPRISING: AN AIR-OIL TANK UNIT HAVING A LOWER CHAMBER FOR CONNECTION WITH THE SYSTEM TO RECEIVE HYDRAULIC LIQUID THEREIN, SAID TANK UNIT HAVING AND UPPER CHAMBER ABOVE THE LOWER CHAMBER WITH MEANS PROVIDING A SINGLE PASSAGE FOR COMMUNICATION BETWEEN THE CHAMBERS AND VALVE MEANS IN SUCH PASSAGE CONNECTING THE CHAMBERS, SAID VALVE MEANS BEING MOUNTED RESPECTIVELY AT A HIGH AREA IN THE LOWER CHAMBER AND A LOW AREA IN THE UPPER CHAMBER, SAID VALVE MEANS HAVING A VALVE CLOSURE RESILIENTLY URGED CLOSED AGAINST PRESSURE IN THE LOWER CHAMBER, SAID VALVE CLOSURE FORMING THE SOLE GAS OUTLET AND BEING RESPONSIVE TO PRESSURE IN THE LOWER CHAMBER IN EXCESS OF SAID RESILIENT URGE TO PASS AIR AND LIQUID FROM THE LOWER CHAMBER INTO THE UPPER CHAMBER, SAID UPPER CHAMBER HAVING MEANS FOR PASSAGE OF THE AIR THEREFROM SAID VALVE MEANS CARRYING A MEMBER RESPONSIVE TO SUCTION IN THE LOWER CHAMBER FOR PASSING ONLY LIQUID INTO THE LOWER CHAMBER FROM THE UPPER CHAMBER. 